Light metal casting

ABSTRACT

A light metal casting for use in combination with a metal holder for mounting heavy subassemblies, such as doors or the like, to a light metal frame member of a light metal vehicle body framework, including a first, vertical leg portion having an outward facing surface to which a metal holder is mounted, and a second, inwardly-extending horizontal leg portion connected at an upper end of the first leg portion. The second leg portion is provided with a vertical through-hole oriented transversely to its surface, and, at the edge of the opening which faces the first leg, an upstanding tongue member is formed integrally on the second leg which points away from the first leg and can be bent over the holder. In order to fasten the holder to the light metal casting, the holder is first placed against the outer side of the vertical first leg, whereupon the tongue is bent in the direction of this outer side of the first leg and turned over the holding part until it presses the latter against the outer side of the first leg to hold it fast against the light metal casting. The holding part can thus be mounted on the light metal casting in a simple manner and very quickly, since it is only necessary to bend over the tongue.

FIELD

This present invention relates to a light metal casting for use inmounting heavy subassemblies, such as doors, on a light metal motorvehicle body framework, and to methods of producing and using thecasting of this invention.

BACKGROUND

There is an increasing trend in motor vehicle body design, and inparticular private passenger car body design, to assemble the vehiclesupporting structure from light metal elements. An example of one suchsystem is known from European Patent Document EP 0 146 716 B1 whichdiscloses a vehicle body assembled from a plurality of extruded lightmetal hollow sections joined together by cast light metal node elements.

A disadvantage which such a light-metal bodywork design however is thatin view of the lower yield strength of the light metal material ascompared with heavy subassemblies, such as for example conventionallyused sheet metal stampings, doors or the like, cannot be directlyfastened to a light metal frame member without additional and oftenexpensive reinforcement.

It has therefore already been proposed to provide on such light metalcastings additional metal holding parts (holders) which serve to holdthe heavy subassemblies. However, in order to mount these holders on thecastings, it is necessary to machine the castings after they are formed.Thus, a relatively considerable expenditure of time is required forfinishing the connection between the holding part and the casting. Thisadditional time increases the cost of assembling the motor vehicle.

Accordingly, there is a definite need in the art for a light metalcasting for use in mounting heavy vehicle subassemblies to a light-metalframe component which does not require additional machining after itsformation in order to receive a metal holder.

THE INVENTION OBJECTS

It is a principal object of the present invention to reduce the time andexpense of mounting a heavy subassembly, such as for example a door orthe like, to a light metal vehicle bodywork.

It is a related object of the invention to provide a light metal castingfor use in mounting heavy subassemblies which can be produced in asimple manner and which is configured to quickly receivingly engage ametal holder without additional machining or great expense.

These and other objects and advantages will become apparent from thefollowing written description, drawings and appended claims.

SUMMARY

The invention comprises an apparatus, its use, method of fabrication ofa light metal casting for use in combination with a metal holder formounting heavy subassemblies, such as for example doors or the like, toa light metal frame member of a light metal vehicle body framework. Theinvention is directed to overcoming the problem of how to mount themetal holder to the light metal casting in a simple, inexpensive andstrong manner.

In accordance with the apparatus aspects of the invention, the lightmetal casting comprises: a first, vertical leg portion having an outwardfacing surface to which a metal holder is mounted; and a second,inwardly-extending horizontal leg portion connected at an upper end ofthe first leg portion. The second leg portion is provided with avertical through-hole oriented transversely to its surface, and, at theedge of the opening which faces the first leg, an upstanding tonguemember is formed integrally on the second leg which points away from thefirst leg and can be bent over the holder.

In order to fasten the holder to the light metal casting, the holder isfirst placed against the outer side of the vertical first leg, whereuponthe tongue is bent in the direction of this outer side of the first legand turned over the holding part until it presses the latter against theouter side of the first leg to hold it fast against the light metalcasting.

The holding part can thus be mounted on the light metal casting in asimple manner and very quickly, since it is only necessary to bend overthe tongue. Since the tongue and the light metal casting are formedintegrally joined to one another during the same casting operation, noadditional machining is required to provide a means for fastening theholding part to the light metal casting.

According to the method aspect of the invention, the light metal castingalong with the integrally formed tongue is produced with the aid of twomold parts including a first mold part which is situated along theinside surface of the first leg portion and a second mold part situatedalong the outside of the first leg portion. The first mold part furtherhas an upward extension which protrudes through the vertical throughhole of the second leg portion. Once the casting process is complete thetwo mold parts are pulled apart in opposite parallel directions suchthat the upward extension of the first mold part moves downward throughand out of the vertical through hole of the second leg portion.

Since the two mold parts are removed in opposite directions to oneanother it is possible to configure the tongue with a cross-sectionalthickness which increase towards its free end. The effect is therebyachieved that the bendability of the tongue can be controlled in adesired manner. For example, when force is applied to the tongue freeend in the direction of the holder, the tongue first bends over at itsbase end directly at the top edge of the second leg and then uponcontinuation of force, the tongue bends downwards at its middle to wrapover pivoting over the upper free edge of the holder.

By way of example, the cross-sectional thickness of the tongue, that isto say the thickness at right angles to the plane of the tongue, may beincreased in steps in order to purposely define the bending regions ofthe tongue and the sequence of the regions of the tongue where bendingis to take place in succession.

Alternately, the cross-sectional thickness of he tongue can increasecontinuously from its juncture at the top edge of the second leg portionin order to locate the first bending region as close as possible to thetop face of the second leg. Upwards from this region, the thickness ofthe tongue may be increased in steps, for which purpose the tongue has astepped projection pointing inwardly (away from) the holder element.These projection(s) thus are spaced above the vertical through-hole inthe second leg. By use of such projection(s), i.e. the increasedthickness of the tongue, the location of second bending region can thenbe determined as required to match the thickness of the holder elementso that it cones to lie above (coordinate with) the front edge of theholder after the tongue has been bent over (parallel to the second leg).

An additional advantageous feature of the invention comprises providinga retaining means on the lower portion of the outer side of the firstleg for fastening the bottom end of the holder to the casting at a pointremote from the tongue. The holder can thus be fastened at opposite endson the light metal casting, so that it is more effectively secured inposition.

The holder bottom retaining means preferably includes an upwardlypointed lug which projects through a perforation or slot formed in thebottom end of the holder.

It is preferred to provide the lug with sufficient upward projection(vertical length) to prevent the holder from tilting downwards orpivoting at right angles with respect to the first leg portion.

In another embodiment of the invention, the holder bottom retainingmeans includes a third leg portion which is integrally formed at thelower, free end of the first vertical leg portion, and on which thebottom end of the holder rests. The third leg portion extendshorizontally in the direction opposite to the upper, second leg portion.The light metal casting inside elevation thus resembles an S-shapedstructure. In order to prevent side-to-side (twisting or pivoting)movement of the holder with respect to the first vertical leg portion, agroove may be provided in the top surface of the third leg portion whichis sized for receiving the bottom end of the holder therein.

The holder may for example be in the form of a plate having a cutout orslot in which the lug is received. The lug may also be fastened both tothe first and to the third leg portions.

For the purpose of supporting heavy subassemblies, such as for exampledoors and the like, the holder is preferably made of high-strengthmaterial, for example steel. Through bores, for example threaded throughbores, may be provided in the holder to enable a door hinge, forexample, to be fastened thereto.

DRAWINGS

The invention is described more fully below with reference to thedrawings, in which:

FIG. 1 is an isometric view of a light metal casting constructed inaccordance with one embodiment of the invention shown with an attachedholder; and

FIG. 2 is a section view through the light metal casting and holdertaken along the line and in the direction of arrows 2--2 of FIG. 1.

DETAILED DESCRIPTION OF THE BEST MODE

The following detailed description illustrates the invention by way ofexample, not by way of limitation of the principles of the invention.This description will clearly enable one skilled in the art to make anduse the invention, and describes several embodiments, adaptations,variations, alternatives and uses of the invention, including what wepresently believe is the best mode of carrying out the invention.

FIG. 1 shows a perspective view of a light metal casting according tothe invention, which is, for example, an aluminum pressure diecasting.The light metal casting is given the reference numeral 1 and has anS-shaped cross-sectional shape. It may, for example, consist of acorresponding sectional bearer member whose longitudinal directionextends from the lower right portion to the upper top left portion inFIG. 1. (The direction of axis X in the 3-D axis orientation guide seenon the left of FIG. 1.)

As can be seen from the present exemplary embodiment, the light metalcasting includes a first upright (vertical) leg portion 2, a second,upper horizontal leg portion 3 and a third, lower, horizontal legportion 4. All the leg portions 2, 3 and 4 are formed integrally joinedtogether, with the second leg portion 3 and the third leg portion 4lying at opposite top and bottom ends of the first leg portion 2 andextending in opposite horizontal directions. The leg portions 2, 3 and 4are preferably in the form of flat plates and may have identical ordifferent wall thicknesses. An angle of 90° is selected both between thefirst leg portion 2 and the second leg portion 3, and between the firstleg portion 2 and the third leg portion 4.

An outer side surface of the first leg portion 2 is given the referencenumeral 2a. A holder 5, which is preferably in the form of a flat steelplate of rectangular shape, lies against this outer side surface 2a ofthe first leg portion 2. The plate 5 therefore lies with one mainsurface directly on the outer side surface 2a. For the purpose offastening a subassembly (not shown) the plate 5 is provided withthreaded through bores 6 which extend at right angles to the plane ofthe plate. Screws can be screwed into these threaded bores 6 in order toconnect, for example, a vehicle door hinge to the plate 5.

Alternately, it is also possible to provide the plate 5 with unthreadedthrough bores (FIG. 2) which are in alignment with corresponding throughbores 7 provided in the first leg portion 2 (see FIG. 2). In this case,in order to fasten a subassembly to the plate 5, threaded bolts, forexample, can be passed through the coaligned bores 6 and 7 and can bescrewed into nuts which lie against the inner side surface 2b of thefirst leg portion 2. Suitable washers may be disposed between the nutsand the first leg portion 2.

The plate or holder 5 stands with its bottom edge on the inner face ofthe third leg portion 4 and is fixed in position by a lug 8. The lug 8is preferably integrally joined to both the leg portions 2 and 4 in thecorner region between the first leg portion 2 and the third leg portion4 and projects through a perforation, slot or cutout 9 provided in theedge of the bottom end of the plate 5. In particular, the lug 8 isconfigured such that its free end 8a projects upwardly towards thesecond leg portion 3. In this way, the free end 8a of the lug 8 engagesthe plate 5 and prevents the plate 5 from movement at right angles withrespect to the first leg portion 2 (i.e, along the Z-axis), as there isa tendency for the plate 5 to pivot away from outer side surface 2awhen, as described below, a tongue and a lug are bent over the top ofthe plate 5 to secure it to the leg 2. For this purpose, the shape andthickness dimension of the free end 8a of the lug 8 and the depth of thecutout 9 are appropriately selected, adjusted to match one another sothat a minimum, or substantially no clearance is left between the topend of the lug 8 and the adjacent edge of the slot 9 in plate 5. Theshape of the top part of the lug 8, starting from the tip region 8a,may, for example, extend in a curve downwards in the direction of thefirst leg portion 2.

In addition, the lug 8 prevents movement of the plate 5 in thelongitudinal direction of the light metal casting 1, that is to sayparallel to the first leg portion 2, (in the direction of the X axis)since the vertical sides of the cutout 9 of the plate 5 lie about thesides of the lug 8 practically without clearance.

Alternately, in order to prevent movement of the plate 5 at right anglesto the first leg 2 (i.e., along the Z-axis), a groove 15 is provided inthe third leg portion 4, disposed adjacent the corner region between thefirst leg portion 2 and the third leg portion 4. The groove 15 ispreferably sized to receivingly engage the bottom end of the plate 5 insnug fit fashion. In the case of a groove, the special configuration ofthe lug 8 in its tip region 8a can be omitted as not necessary.

In order to fasten the plate 5 in its top region to the first legportion 2, it is provided with a cutout 5a in its top end edge. Thisedge cutout 5a extends downwards into the plate 5 to such a depth thatthe bottom of the cutout is in substantial vertical alignment with thetop surface of the second leg portion 3. In this way, left and rightside projections or ears 5b are formed at the top end of the plate 5.

The width of the edge cutout 5a is sized to receive and center a tongue10, which when forwardly (i.e., in the direction of the Z axis) anddownwardly bent (Arrow E, FIG. 2) comes to lie between the sideprojections 5b of the plate 5 in order to fasten the plate 5 to thecasting 1. As shown in FIG. 1 the tongue 10 is in the unbent state.

As FIG. 1 shows, the second leg portion 3 is provided with a throughhole 11 of generally rectangular shape.

The longer sides of the through opening 11 extend parallel to the outerside surface 2a of the first leg 2 and therefore parallel to the plate5. The tongue 10 is integrally formed on the second leg 3 at that edgeof the through opening 11 which faces (is closest to) the first leg 2.The tongue 10 projects upwards and extends substantially at right anglesto the second leg 3 and parallel to the first leg 2, in the directionaway (i.e., along the Y axis) from leg 3.

A bottom region 12 of the tongue 10 is provided with a thin wall, whichmeans that the tongue 10 has only a slight thickness at right angles toits plane. On the other hand, a projection or lug 13 is formed at thefree end of the tongue 10, that is, a region of relatively thickmaterial, viewed in a direction at right angles to the plane of thetongue. The thickness of the projection or lug 13 extends parallel tothe plane of the second leg portion 3, that is, in the lateral direction(i.e., along the Z-direction) of the light metal casting 1, and inaddition lies above and projects into the projection of the throughopening 11. It is therefore situated on the side of the tongue 10 remote(opposite) from the plate 5. That side of the tongue 10 which faces theplate 5 is completely flat and extends at right angles to the surface ofthe second flange 3.

As shown in FIG. 1, the tongue 10, viewed at right angles to the planeof the tongue, may have a trapezoidal cross-section, the width of thetongue being greater adjacent the upper face of the second leg portion 3than at the free end of the tongue. The thickness of the tongue 10 inFIG. 1 is constant in the bottom region 12, but, in an alternateembodiment, its thickness may increase continuously in the Y-directiontoward its free end (i.e, tapered or stepped), although for the sake ofclarity this has not been shown in detail in the drawing.

Through the selection of the thickness of the tongue 10, viewed in FIG.2 at right angles to the plane of the tongue, bending regions for thetongue 10 can be defined, that is regions in which the tongue 10 caneasily be bent in succession. In particular by means of a trapezoidalthickness pattern at right angles to the plane of the tongue, with thethickness of the tongue 10 at its minimum in the immediate vicinity ofthe second leg portion 3, it is possible to bring a first bending region20 of the tongue 10 very close to the second leg portion 3. A secondbending region 22 of the tongue 10 is obtained in the transition of theshoulder 24 of the still thicker projection or lug 13.

If therefore a force is first applied to the tongue 10 in the directionof the arrow A in FIG. 1, it will first bent at 20 (FIG. 2) in itsbottom region 12 near the second flange 3 or, e.g., in the case of atrapezoidal thickness pattern, it will bend at the edge of the throughopening 11. The tongue 10 then first lies horizontally, projecting intothe edge cutout 5a. The width of the tongue 10 in the longitudinaldirection, (X, X) of the light metal casting 1 can be so selected thatno substantial clearance is left between the edges 12a of the tongue 10and the projections 5b, so that even at this stage the tongue 10prevents the pivoting or tipping of the plate 5 in its own plane. Thetaper of edges 12a help center the tongue and the plate 5. If the lug 13of tongue 10 is then bent over further with greater exertion of force(arrow E, FIG. 2), it will bend in the bending region 22 between thebottom region 12 and the lug 13, so that finally the rear side 13a ofthe projection 13 presses against the free side of the plate 5 andsecures the latter to the leg 2. The height of the bottom region 12above the second leg 3 is selected so that, after the tongue 10 has beenbent over by 90°, the bending region between the bottom region 12 andthe lug 13 is aligned with the front, free edge of the plate 5.

FIG. 2 shows a cross-section along the line 2--2 in FIG. 1, that is, asection at right angles to the longitudinal (X, -X) direction of thelight metal casting 1. The tongue 10 is shown in phantom in the bentover conditions with plate 5 being secured against the outer side 2a ofthe first flange 2.

As can be seen, in the process of molding of the light metal casting,plate 5 not being present, a mold part 14 (shown in phantom) projectsfrom below through the opening 11 which is being formed in the secondleg portion 3, and serves to produce the special thickness configurationof the tongue 10 in its bottom region 12 and to form the step orshoulder 24 between the region 12 and the lug 13. After the molding ofthe light metal casting 1, the mold part 14 is pulled out downwards,that is oppositely to the direction in which the tongue extends, fromthe through opening 11 in the direction of the arrow B in FIG. 2. Theparting plane is given the reference C in FIG. 2. Through the specialarrangement of the mold part 14 in the molding of the light metalcasting 1 the thickness of the tongue 10 at right angles to the plane ofthe tongue can thus be adjusted in the desired manner in the bottomregion 12, such that it increases towards the free end of the tongue inorder in this way to be able to determine defined bending regions, whichextend parallel to the surface of the second leg portion 3, within thetongue 10.

The second mold part, which is not explicitly shown in FIG. 2, issituated on the right-hand side of the tongue 10 in FIG. 2, that is onthe right of the first leg 2 and above the third leg 4. After themolding of the light metal casting 1 it is removed in the direction ofarrow D, that is it is pulled upwards in FIG. 2.

It should be understood that various modifications within the scope ofthis invention can be made by one of ordinary skill in the art withoutdeparting from the spirit thereof. We therefore wish our invention to bedefined by the scope of the appended claims as broadly as the prior artwill permit, and in view of the specification if need be.

We claim:
 1. A light metal casting for use in mounting heavysubassemblies on a light metal vehicle framework, comprising inoperative combination:a) a first leg having an outer side surface; b) asecond leg having a through opening extending transversely to its legsurface, said through opening having an edge facing said first leg; c) aholder fastened to said outer side of said first leg; d) a tongue formedintegrally at said edge of said through hole opening and disposed onsaid second leg, said tongue includes a free end pointing away from saidfirst leg and which can be bent over said holder, and said tongue has across-sectional thickness increasing towards its free end.
 2. A lightmetal casting according to claim 1, characterized in that saidcross-sectional thickness of said tongue increases in steps.